An man described by police as an internet predator promised marriage or a long term relationship to three women he scammed after meeting them through an online dating site.

The 46-year-old claims he was driven to go on the dating site by loneliness and depression after separating from his partner.

Shane William Grogan, also known as Shane Calder, formed three online relationships lasting between one and three weeks with women in Rotorua, Palmerston North, and South Canterbury, and stole from all of them.

Grogan travelled to meet all three of the women he met on-line, and stayed with them in relationships, before leaving with cars, cash, and belongings.

At Grogan's Christchurch District Court sentencing, Judge Tony Couch said the emotional effect on all the victims had been severe. The North Island women were aged in their 50s, the South Canterbury woman was aged in her 30s.

Defence counsel Ruth Buddicom said there had been a significant downturn in Grogan's dishonesty offending since 1996. He had pleaded guilty, and had made a real - and largely successful - effort to help police recover property he had stolen.

Twelve of 14 stolen rings had been recovered, and reparation was sought for two that were not found.

Grogan had pleaded guilty to two charges of stealing from homes, unlawfully taking cars, dishonestly using a document, breach of a protection order, and breach of a community work sentence.

Buddicom said Grogan had been in custody since his arrest in March - the equivalent of an eight month jail term. She said the context of the relationships must be seen as "a risky process".

Police publicity at the time of Grogan's arrest had encouraged other victims to come forward with complaints but none had done so.

Judge Couch described Grogan's offending as "the repeated cynical exploitation of vulnerable women". In one case, rings worth $10,000 had been stolen by Grogan with his abrupt departure. He had taken cars and debit cards, and other belongings including tobacco and a Playstation.

He said internet dating sites offered the opportunity for lonely and vulnerable people to meet others, to look and hope for the best in people they met. "You took advantage of that."

One woman said in her victim impact statement: "I have never been treated as well as he treated me. After he stole from me, I realised it had all been a lie. This has been distressing and upsetting for me."